Modular braking adjuster with hybrid design

Abstract

A modular braking adjuster includes a brake resistor and at least two sub-modules arranged in series. At least one sub-module is constructed as a full-bridge module and at least one sub-module is constructed as a double half-bridge module. A control device is configured to generate a voltage across the serially connected sub-modules, wherein the voltage has a direct voltage component and an alternating voltage component. The control device provides open-loop or closed-loop control of the alternating voltage component, such that the alternating voltage component is at least temporarily greater than the direct voltage component and the time-averaged energy taken up by the modular braking adjuster is converted into heat in the brake resistor. An electric drive having the modular braking adjuster and a power converter electrically connected on the direct voltage side to the modular braking adjuster and a method for operating a modular braking adjuster are also disclosed.

What is claimed is: 
     
       1. A modular braking adjuster, comprising:
 a brake resistor and at least two submodules, wherein the brake resistor and the at least two submodules are connected to form a series circuit, wherein at least one submodule is constructed as a full-bridge module and at least one submodule is embodied as a double half-bridge module, and 
 a control device configured to 
 generate a voltage across the serially connected submodules, with the voltage composed of a direct voltage component and an alternating voltage component, 
 to control with the direct voltage component by open-loop control or closed-loop control power to be converted into heat by the modular braking adjuster, 
 to control an amplitude of the alternating voltage component by open-loop control or closed-loop control in such a way that the energy taken up by the modular braking adjuster averaged over time is converted into heat in the brake resistor, wherein the amplitude of the alternating voltage component is at least temporarily greater than the direct voltage component, and 
 to at least temporarily generate a negative proportion of the current through the modular braking adjuster for maintaining an energy balance. 
 
     
     
       2. The modular braking adjuster of  claim 1 , wherein the alternating voltage component has a periodic curve and an average value of zero. 
     
     
       3. The modular braking adjuster of  claim 1 , wherein at least one of the at least two submodules has a bypass switch configured to short-circuit terminals of the at least one submodule. 
     
     
       4. The modular braking adjuster of  claim 1 , wherein all of the at least two submodules have a bypass switch configured to short-circuit terminals of the submodules. 
     
     
       5. An electric drive, comprising:
 a modular braking adjuster as set forth in  claim 1 ; and 
 a power converter electrically connected on a direct voltage side to the modular braking adjuster. 
 
     
     
       6. The electric drive of  claim 5 , wherein the power converter is constructed as a modular multilevel power converter. 
     
     
       7. A method for operating an electric drive as set forth in  claim 5 , the method comprising:
 generating with the submodules a voltage across the serially connected submodules, which, at least temporarily, comprise a negative and a positive voltage range, wherein the voltage comprises a direct voltage component providing open-loop or closed-loop control of the power to be converted into heat by the modular braking adjuster and an alternating voltage component, wherein the alternating voltage component is controlled by open-loop control or closed-loop control such that the energy taken up by the modular braking adjuster averaged over time is converted into heat in the brake resistor, wherein an amplitude of the alternating voltage component is at least temporarily greater than the direct voltage component, and 
 generating at least temporarily with the modular braking adjuster a negative proportion of the current for maintaining an energy balance. 
 
     
     
       8. The method of  claim 7 , wherein the alternating voltage component has a periodic curve and an average value of zero. 
     
     
       9. A method for operating a modular braking adjuster as set forth in  claim 6 , the method comprising:
 generating with the submodules a voltage across the serially connected submodules, which, at least temporarily, comprise a negative and a positive voltage range, wherein the voltage comprises a direct voltage component providing open-loop or closed-loop control of the power to be converted into heat by the modular braking adjuster and an alternating voltage component, wherein the alternating voltage component is controlled by open-loop control or closed-loop control such that the energy taken up by the modular braking adjuster averaged over time is converted into heat in the brake resistor, wherein an amplitude of the alternating voltage component is at least temporarily greater than the direct voltage component, and 
 generating at least temporarily with the modular braking adjuster a negative proportion of the current for maintaining an energy balance. 
 
     
     
       10. The method of  claim 9 , wherein the alternating voltage component has a periodic curve and an average value of zero.